Garlic is an herb very low in calories, saturated fats, and sodium. It contains a number of useful minerals such as phosphorus, potassium, magnesium, zinc, calcium, and iron, as well as trace minerals like iodine, sulfur, and chlorine. According to the USDA National Nutrient Database, garlic is a rich source of B-vitamins (folate, thiamine, niacin, and B-6), and vitamins C, A, and K. Garlic is one of the rare dietary sources of organic compounds, allicin, allisatin 1, and allisatin 2.